1. Field of the Invention
The present invention relates to a method for continuous bleaching of a cloth or particularly a cotton cloth by using a high pressure steamer.
2. Description of the Prior Art
In bleaching a cloth continuously using hydrogen peroxide, such processes have conventionally been adopted as to subject the cloth to wet-heat treatment for about 1 hour continuously by using a loading-type PERBLE RANGE (Trade Mark of a wet-heat treatment apparatus) or a J-box, to subject the cloth to steaming for 5 to 10 minutes in an ordinary pressure steamer body, and to utilize a rabit bleaching method. However, in any of these bleaching methods, while the whiteness can be satisfied as a whole, the removal of spots has been very difficult in the case when the raw cloth has numerous black or brown spots. For the removal of the spots, it has conventionally been adopted to subject the cloth repeatedly to alkaline scouring prior to bleaching or to repeat bleaching with use of concentrated hydrogen peroxide solution, but these processes have such defects that treating agent, heat energy and treating time are consumed in vain and the strength of the resultant cotton cloth is deteriorated.
In a loading-type wet-heat treatment by using PERBLE RANGE, in which steaming and boiling are made simultaneously, the above defects can be dissolved to some extent, but, in this instance, since the water content of the cloth (bath ratio) is low, soaking of the cloth with hydrogen peroxide solution must be repeated even when a concentrated treating solution is used.